VDB to Maya

[Zabander]

Hello friends, I have an issue with vDB, when I export from Houdini to vray in maya I have no access to motion blur, the only way I find is to export the VDB is with volume rasterize particles node, but the motion blur is baked and cant be turned on or off in vray and the velocity pass in vray is empty. How can I export the VDB with a velocity channel ?

 

Regards,

Edited April 5, 2016 by Zabander

[fathom]

does your volume in houdini have a "vel" field?

 

how are you generating it?  if you use dop import fields, you have to make sure to import the vel fields... then it should "just work" when rendering from vray.

Edited April 6, 2016 by fathom

[Zabander]

Yes, I use the import fields and it brings the vel field as invisible, later I use the rasterize particle node and then a ROP output node to export the VDB file. But it seems that the velocity doesnt arrive to Maya.

[danw]

I've never used vray, but could it be something as simple as it expecting the velocity to be named something other than "vel"?  Maybe try renaming it "v" or "velocity"?

[anim]

names density and vel should work fine for VRAY

 

the problem probably is rasterize particles, it sounds like you are converting particles? what is your data?

if you have vel field before rasterize particles, it will be gone afterwards as only particles are used to sample the data to empty volume

so you may need to merge the vel field afterwards or rasterize v from particles to new vel volume

do you have an example file? 

 

EDIT: but if your sim is pyro or smoke, then just use Convert VDB (in Convert To VDB mode) instead of rasterize particles

Edited April 6, 2016 by anim

[Zabander]

It is for whitewater, if I rasterize the vel in the VDB I lost the control over it, and would not be able to get velocity pass. How can I merge the vel field afterwards?

I will prepare an small test file.

[fathom]

you can merge the velocities simply with a merge sop.